by Trevor Hughes, USA TODAY

by Trevor Hughes, USA TODAY

Drivers in America's national parks are killing the very bears, deer, wolves and other animals they're hoping to see, says a new report seeking changes to the way park managers deal with conflicts between cars and wildlife.

"The wildlife is being sacrificed in order to be viewed," says Jeff Ruch, executive director of Public Employees for Environmental Responsibility, which researched roadkill deaths in national parks. PEER said the 401-unit national park system lacks a systematic way of tracking when wildlife is hurt or killed by drivers, making it hard to reduce roadkill and to gather an accurate count of the national toll.

The public employee group filed Freedom of Information Act requests to collect some snapshots of the toll in some national parks. Yosemite National Park officials, for instance, reported that 300 black bears were struck by cars from 1995-2012, but couldn't say exactly how many of those died from injuries later. Park officials even launched a campaign to warn drivers about the potential for collisions, but discovered park visitors were stealing the warning signs, PEER found.

Scott Gediman, a 17-year ranger at Yosemite, says speed is the biggest factor in wildlife collisions. He says rangers post and enforce speed limits, educate visitors and sell mugs and T-shirts with the "Speeding Kills Bears" message on them. He says rangers have to chain up the signs because they were getting stolen for souvenirs by visitors.

"It's always a struggle to make sure our wildlife is safe," he says. "We certainly want people to see the park."

Total reported roadkill in Yosemite was 20 in 2009, 21 in 2010, hit 33 in 2011 but fell to 24 in 2012. In Grand Teton National Park in Wyoming, the number of large mammals (more than 30 pounds) killed in vehicle collisions climbed 205% from 1991 to 2011.

Managing conflicts between millions of visitors and millions of animals is a constant balancing act for park managers, says Joan Anzelmo of the coalition of National Park Service Retirees and a 35-year NPS veteran.

The National Park Service is congressionally mandated to "conserve the scenery and the natural and historic objects and the wildlife therein and to provide for the enjoyment of the same in such manner and by such means as will leave them unimpaired for the enjoyment of future generations."

Anzelmo says roadkill deaths are both "regrettable" and all-but-inevitable, because America's national parks were designed to give visitors access to a world they might not otherwise see.

"There's wonder around every corner, and you have to be prepared for that when you're driving in this area," says Anzelmo, the former superintendent of Colorado National Monument who now volunteers at Grand Teton.

Ruch says park managers need a nationally consistent approach to tracking and reducing the number of roadkill deaths. He says road improvements that aim to help drivers move faster through parks are increasing collisions.

In Yellowstone, for instance, drivers often brake suddenly when they spot bison, bears or elk. That can cause fender-benders, and so park managers installed more viewing pullouts - but that leads to other drivers speeding through the area and colliding with the same animals other people are looking at, Ruch says. He says park managers should consider installing overpasses or underpasses to help reduce collisions, better study how roadway changes might affect collision rates, and even consider replacing private vehicle traffic with shuttle buses.

"In some cases, vegetation in the median strip functions like a salad bar, drawing animals into harm's way," he says. "Once hit, the resulting carcass attracts scavengers who, in turn, get hit by passing cars."

PEER singled out Grand Teton's managers for praise - slower nighttime speed limits and flashing warning signs prompted a drop in wildlife collisions last year. "We've seen some steady progress, but there's lots more to be done," Anzelmo says. "There are still way, way too many animals being hit."

Three million visitors annually enter Rocky Mountain National Park in Colorado, many of them driving over Trail Ridge Road, the highest paved road in America. The road winds through meadows filled with elk and mountains populated by bighorn sheep.

While animal deaths caused by drivers in the park are few, says Chief Ranger Mark Magnuson: "On the rare occasion in this park when we do lose an animal ... it's sad. It's part of the natural order when a pack of coyotes takes down an elk calf. You ask yourself, when you have a motor vehicle that strikes an elk calf, is that the natural order? We're all part of the natural order, but we've come in and built roads. Anytime you mix the two, the opportunity for accidents is there."